Distorted Asymmetric Cubic Nanostructure of Soluble Fullerene Crystals in Efficient Polymer:Fullerene Solar Cells
journal contributionposted on 22.09.2009, 00:00 by Youngkyoo Kim, Jenny Nelson, Tong Zhang, Steffan Cook, James R. Durrant, Hwajeong Kim, Jiho Park, Minjung Shin, Sungho Nam, Martin Heeney, Iain McCulloch, Chang-Sik Ha, Donal D. C. Bradley
We found that 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)C61 (PCBM) molecules make a distorted asymmetric body-centered cubic crystal nanostructure in the bulk heterojunction films of reigoregular poly(3-hexylthiophene) and PCBM. The wider angle of distortion in the PCBM nanocrystals was ∼96°, which can be assigned to the influence of the attached side group to the fullerene ball of PCBM to bestow solubility. Atom concentration analysis showed that after thermal annealing the PCBM nanocrystals do preferentially distribute above the layer of P3HT nanocrystals inside devices.